The present invention relates generally to a closure for drinking vessels and, more particularly, to a closure which is self-sealing. The closure of this invention may be opened by thumb pressure in order to remove liquid from the drinking vessel. However, once the thumb pressure is released, the closure automatically returns to its closed position.
Many closures for drinking vessels have been provided by the prior art. Frequently these vessels are used by one who is also engaged in other tasks such as, e.g., driving, riding in a vehicle, or working at a place of employment.
There is a need for a spill-proof drinking vessel which can be easily used by a consumer of liquid. Preferably, such a consumer should be able to open such vessel with only one hand and with the exertion of only a minimal amount of pressure; and, in order to insure that liquid does not spill from the vessel once the consumer has finished drinking from it, the vessel should close automatically once the consumer has put it down.
Many of the drinking receptacles currently used by the public are relatively inexpensive. The closure for the drinking vessel also should be relatively inexpensive.
One of the closures for drinking vessels provided by the prior art is described in U.S. Pat. No. 4,171,060. Although the closure of this patent can be opened with a minimal amount of thumb pressure, it does not appear that the closure automatically returns to its closed positon when the thumb pressure is released.
It is an object of this invention to provide a closure for drinking vessels which is relatively inexpensive to produce, which can be operated with only one hand, which can be opened with the application of only a minimal amount of pressure, and which closes automatically when the pressure is released.